1. Field of the Invention
The present invention relates to a radio communication apparatus. More specifically, the invention relates to an expansion of the functional capabilities of the radio communication apparatus. The expansion provides for the checking of the various functional settings previously made for performing communication to determine if any of the settings have been modified at a later stage before resumption of the communication, and if so, notification is made to facilitate restoration of the functional settings to their original states.
2. Description of the Related Art
In recent years, most radio communication apparatuses contain a microcomputer circuit therein to allow control of various functions by manipulating switches and dials.
Thus, a plurality of push-button switches and dial knobs are provided for an operation panel of a radio communication apparatus. A lot of radio communication apparatuses employ a system of displaying on their liquid display section settings associated with main functions.
To take an example, as shown in FIG. 6, a main unit 1 of an amateur radio transmitter-receiver has a plurality of switches and knobs disposed in a rational manner for ease of operation. Further, several switches are provided in a microphone 2 for enabling quick operation. The specific functions of these switches and knobs are as follows:    (1) An AF volume knob 11 adjusts a received sound volume.    (2) An SQL (squelch) knob 12 is used for eliminating noise in the absence of a signal.    (3) The SQL knob 12 serves as an RF GAIN knob 13 as well. The RF GAIN knob 13 is used to adjust a gain of a receiving section. According to a selected menu mode, switching is performed between the RF GAIN knob 13 and the SQL knob 12.    (4) A CLAR (clarifier) switch 14 is employed when a SELECT knob 15 is used to perform a CLAR function of changing a receiving frequency alone without changing a transmitting frequency.    (5) The SELECT knob 15 is used to perform functions of setting a frequency, selecting a memory channel, setting an IF shift, clarification, and selecting a menu mode by switching, according to an operation status.    (6) A multifunction switch 16 is used to perform various functions, and the assigned functions to be performed are switched by a FUNC switch 18.    (7) A DSP (digital signal processor) switch 17 controls a built-in DSP to perform switching between a DSP NR, a DSP AUTO NOTCH, a DSP BPF mode. The DSP NR is a function of canceling a succession of noise in the frequency band, and the DSP AUTO NOTCH is a function of reducing a beat tone of a received signal. The DSP BPF is a function of controlling a lower cut-off frequency a higher cut-off frequency separately in a BPF function of the DSP to remove radio interference and compensate a receiving frequency response, and adjusting a BPF center frequency to follow a BFO pitch in a CW mode.    (8) A FUNC (function) switch 18 switches the assigned functions of the multifunction switch 16.    (9) UP and DWN (down) switches 19 switches operation bands.    (10) A MODE switch 20 switches emission modes, and each time the switch is turned ON, the mode is sequentially switched from an LSB, a CW, an AM, to an FM mode. Further, each time the switch is continuously pressed for five seconds or longer, the mode is sequentially switched from a USB, a CWR, a DIG, to a WFM mode.    (11) An indicator lamp 21 shows a transmission/reception status. The indicator lamp 21 turns red in a transmit mode and turns green in a receive mode.    (12) Though a DIAL (dial) knob 22 is mainly used to make a frequency adjustment, it also makes various adjustments according to functional settings made by the FUNC switch 18.    (13) A PWR (power) switch 23 turns power ON or OFF.    (14) A VFO/MR switch 24 performs switching between a VFO scanning function and a memory channel scanning function.    (15) A STEP switch 25 switches steps during the frequency adjustment.    (16) A HOME switch 26 calls various frequencies used frequently.    (17) A LOCK switch 27 locks settings that have been made by using switches and knobs on the operation panel.    (18) A PTT switch 28 sets the transmit mode when turned ON, and sets the receive mode when turned OFF.    (19) UP and DWN (down) switches 29 perform the same control as the UP and DOWN switches 19 in the main unit 1.    (20) A LOCK switch 30 performs the same control as the LOCK switch 27 in the main unit 1.    (21) An ACC switch 31 calls a home channel of a frequency band being currently used.    (22) A P switch 32 performs the same control as the VFO/MR switch 24 in the main unit 1.    (23) P1 and P2 switches 33 are used for a shift from a lower frequency band to a higher frequency band in a step set by the STEP switch 25.
Recently, various functions of a radio communication apparatus are realized or utilized in the above-mentioned manner by manipulation of a single switch or knob or a combination of any of switches and knobs. Essential data in functional settings made by this manipulation is displayed on a liquid crystal display section (indicated by reference numeral 40 in FIG. 6) in the form of numbers and icons.
In the case of the amateur radio transmitter-receiver described above, the number of functions set by various manipulations often exceeds one hundred functions, and even if they are confined to the main functions used frequently during normal operation, the number of the main functions often exceeds a dozen.
Accordingly, even a skilled operator seldom correctly grasps all of the functional settings during operation. Let us assume the case where communication has been suspended for a change of operator and then communication is resumed by the former operator. In this case, complete restoration of the original functional setting states is extremely difficult, if any of the modifications in the functional settings has been made after the change of operator.
If the settings made by using the switches and knobs are locked by means of the LOCK switch 27, the operation by the subsequent operator becomes invalid. Thus, a modification in the functional settings can also be made invalid. However, when communication is made by the subsequent operator, switching of the transmit and receive modes by means of the PTT switch 28 alone becomes valid. Functional settings to other radio modes and frequencies, and communication with a change in the received sound volume, however, cannot be performed.
Further, by means of the HOME switch 26, the return to several home channels alone can be performed. However, these channels have to be registered in advance, and a channel to be used is changed frequently in a step-by-step manner during practical operation. For this reason, use of the HOME switch is not effective in solving the problem described above.
Further, in automobile-mounted radio communication apparatuses, an unintended erroneous operation tends to occur. To take an example, inadvertent touching on a dial instead of a switching operation to cause a change in frequency can be pointed out.
In such a case, in order to continue the communication that has been being performed so far, it is necessary to urgently restore the functional settings to their original states. However, the operator is not informed of the immediately preceding functional settings, so that in this situation, he is often at a loss as to what to do.